The invention relates to a combination storage and mixing container, including two compartments separated by a valve. The ingredients contained within each compartment are generally co-reactive, thus requiring an effective seal to prevent a premature chemical reaction. The valve means disclosed herein effectively performs this important dual function of isolating and uniting the two chambers for storage and mixing respectively.
The prior art discloses several different structures which are said to perform the above-mentioned dual function. For example, Solowey U.S. Pat. No. 3,340,873 discloses a rupturable diaphragm which isolates the two chambers until such time as mixing is desired. Muhlbauer U.S. Pat. No. 3,655,035 employs a frangible foil bag to store one of the components, a mixing chamber containing the other, and means to rupture the foil bag for mixing.
The major drawback with either approach becomes apparant in situations where mixing of the components in precise proportions is a necessity. Such is the instance where dental restorative material must be prepared from an accurate mixture ratio of an alloy and mercury.
Each approach disclosed by the cited prior art fails to allow the mercury to mix completely with the alloy. The rupturable diaphragm arrangement does not permit all the mercury to flow into the mixing chamber; some mercury remains adhered to the walls of the mercury storage chamber. Similarly, where a frangible foil bag is used to store the mercury, mercury tends to hang in the pouch through part of the triturating period, and this results in incomplete amalgamation. In addition, some mercury is usually retained within the pouch, sometimes producing a final restorative material with a lower ratio of mercury than is clinically acceptable.
The present invention, by using two separate storage chambers separated by a valve under conditions of extremely close tolerance provides for complete amalgamation and accurate mixture ratios. When the valve is actuated, the two chambers are unified into a single mixing chamber. Thus, making the mercury storage chamber an integral part of the amalgamation chamber ensures the aforementioned goal of thorough amalgamation and consistently precise mercury ratios.